The Army band was warming up, the sound checks were still taking place, and Beth and Steve Sammis were standing in the sunshine in the Seaport, talking about their son, Ben.

Marine Captain Ben Sammis, from Rehoboth, was killed in Iraq in 2003 when the helicopter he was piloting went down in combat. His parents stood there, talking about Ben’s virtues, about what they miss most, when his dad said this:

“It’s the way Ben took care of his friends.’’

And in saying that, Steve Sammis captured best what happened Friday when the Massachusetts Fallen Heroes memorial was dedicated.

As impressive as the memorial is architecturally, as remarkable as it is for injecting real soul into what is largely a soulless, ever-expanding section of the city, the memorial is just the physical manifestation of something far more profound.

The mostly Boston cops and firefighters, all military veterans, who made this happen — among them Greg Kelly, Dan Magoon, Mike Brown, Chris Lessard, Jesse Flynn — were determined to recognize the ultimate sacrifice made by the more than 200 men and women from Massachusetts who died in military service since 9/11. They wanted all those Gold Star families to have a place to remember, they wanted future generations to have a place to reflect, to know of that sacrifice and respect it.

Kelly couldn’t be there: his Army special forces unit is deployed right now in a place none of us want to be. It was a poignant reminder that we still have people in harm’s way, that more names will eventually be added to the glass wall of the memorial.

But what is really special about the people who put up that memorial, about the Gold Star families who sat in row after row, is not just the respect they show the dead, but the concern they show the living. The people from Mass Fallen Heroes value their brothers and sisters in arms, the living and the dead, honoring the latter, advocating for the former.

Which brings me to the First Battalion of the 25th Marines. They are New England’s Marine regiment. Their members fired the 21-gun salute when the memorial was dedicated. One of the names on the memorial is Lance Corporal Eric Valdepenas, a kid from Seekonk who left UMass Amherst to deploy to Fallujah with the 1/25th in 2006.

Valdepenas and other members of the 1/25th performed one of the most extraordinary, selfless acts of the war in Iraq. During a search for the triggerman who detonated an IED that just missed their Humvee, Chris Walsh, Third Platoon’s Navy corpsman, came across an infant girl who was dying from a rare bladder condition. Walsh put down his gun and picked up the child, Baby Mariam.

At chow that night, Walsh stood up and asked for volunteers to make discreet, nocturnal visits to Baby Mariam’s house, so he could keep her alive. One by one, the Marines’ hands went up. They dodged IEDs all day, then spent nights saving Baby Mariam. They parked their Humvees a mile away and took circuitous routes to her house on foot, their secret visits aimed at avoiding the scrutiny of local insurgents. It was ridiculously dangerous, but they eventually got her to Massachusetts General Hospital for life-saving surgery.

On Labor Day morning, 2006, Third Platoon was on a routine patrol when their Humvee took a belly shot from an IED, directly beneath. Valdepenas, Walsh, and Corporal Jared Shoemaker were killed.

“It could have been any of us,’’ Jonathan Goldman said. “First and Fourth Platoons were in the same four or five block area.’’

Goldman, a Brookline guy, was a member of First Platoon.

That night, hours after Third Platoon was devastated, Goldman and other members of First Platoon were back outside the wire, and they got hit. The driver, Pat Murray, lost his right leg. Shane Burke, a Boston police officer who was riding shotgun, lost half of his left leg. Goldman, who was manning a machine gun in the turret, suffered shrapnel wounds and burns.

Goldman was lying in a hospital bed when the battalion commander came by and said, “Bad night, huh?’’

“Sir,’’ Goldman replied, “bad day.’’

Those Marines came back home and went back to work. Burke went back to the police department as a crime scene tech. Murray’s working construction. Goldman works in real estate.

Every year, they go to the Semper Fi luncheon at the convention center, and a couple years ago, Goldman bumped into Lieutenant Colonel Chris Graves, the current commander of the 1/25th. Graves said he wanted to get the Marines who served in Iraq together, ten years after their deployment, to see how everybody was doing.

“Sir,’’ Goldman replied, “like a reunion?’’

“Yeah,’’ Graves replied. “A reunion.’’

Such reunions tend to be of smaller groupings. But Graves was proposing a reunion of a whole battalion, 800 Marines and Navy corpsmen. Goldman put some feelers out, and the response was positive.

With help from the Semper Fi Fund, they booked the Marriott Copley for Oct. 8 and since last September have been raising money, so they can bring people in from all over the country. They’ll be hosting 11 Gold Star families.

Goldman said the fund-raising has been harder than expected.

“We’ve been turned down more than we’ve been said yes to,’’ he said. “No one is going to miss this because of money. We will not stop until we get everybody to Boston.’’

There is an ulterior motive for the reunion. It is not just an occasion to literally tell war stories. It is more than an opportunity to tell the Gold Star families that their lost loved ones will never be lost in the memories of the Marines and corpsmen who made it back.

It is, Jon Goldman says, a chance to make sure every member of their battalion is OK.

“We’re not going to belabor it,’’ Goldman said. “We just want everybody to know it’s OK to ask for help.’’

Ten years after the 1/25th took home a disproportionate number of Purple Hearts, the casualties of war continue. Just last year, three Marines from Charlie Company killed themselves.

In the back of the new memorial in the Seaport, there is a grove of five trees. Those trees are dedicated to those who made it back from the hell that was Iraq and Afghanistan only to perish in their own hell, at their own hand.

At a time when so few Americans have volunteered to serve in a period of sustained armed conflict, the new memorial in the Seaport, unveiled just in time for Memorial Day, is especially needed and welcome.

It does more than honor the dead. It reminds us of the obligation we have to take care of those who made it home. The people whose names are on that wall would insist on it.

Kevin Cullen is a Globe columnist. He can be reached at cullen@globe.com. Follow him on Twitter @GlobeCullen.